Conventional regenerative braking systems may use the vehicle's momentum to recharge a battery or other energy storage device as the vehicle is decelerated. During regenerative braking, the vehicle motor may effectively operate in a reverse direction, or more specifically as a generator. The amount of braking effort provided by the regenerative braking system may be a function of the battery charging amperage.
Certain types of vehicle brake systems may include both a hydraulic brake system and a regenerative braking system. In industrial vehicles such as forklifts, regenerative braking may be applied when the operator removes their foot from the accelerator pedal, such that regenerative braking may gradually slow the forklift down. However, when the operator presses on the service brake pedal, a mechanical or hydraulic brake system may be actuated in order to brake the vehicle to a stop. The amount of braking force provided by the hydraulic brake system is typically a function of how much pedal effort is being applied by the operator.
While most of the energy from relatively gentle braking can be recovered in the regenerative braking system, any excess energy that is created from heavy braking in particular, and that is over the charging limits of the regenerative braking system, may be wasted as heat. As a result, known braking systems may be designed to control or balance the brake forces associated with the regenerative braking system and the hydraulic brake system to minimize the amount of energy lost to heat and friction. However, this creates a complexity in braking system design and presents challenges in providing the operator with a consistent and expected operating experience as the vehicle attempts to integrate the two types of braking systems.
Some types of electronic braking systems may be configured to generate a particular pedal stroke response as the brake pedal is being pressed by the operator. However, when the vehicle transitions to the hydraulic brake system, such as when the service brakes are applied, the operator may experience a significant change in effort required to press the brake pedal as a result of the hydraulic fluid being forced into the brake lines of the hydraulic brake system.
This application addresses these and other problems.